1. Field of the Invention
This invention relates to a disc loading/unloading apparatus suitable to use for disc players such as compact disc players and video disc players.
2. Description of the Prior Art
As is well known, in the fields of audio equipment and video image equipment, for example, compact discs and video discs have been developed in which information signals such as sound signals and image signals are converted into a digitalized data, and are recorded on a disc for reproducing a record having as high density and as high fidelity as possible. As a result, disc loading/unloading apparatus have been made as versatile and sophisticated as the compact disc players and video disc players which reproduce audio and video information from such compact discs and video discs.
In recent years, introduction of compact disc players described above into use in automobiles, that is, so-called car-use, has been promoted. In this case, for a compact disc player for auto installation, a disc loading/unloading apparatus of the so-called slot-in type has been used. In these disc players, when an operator of the disc player pushes a disc into a disc receiving slot or a disc insert port of the player up to a fixed depth, the disc is automatically pulled inside the disc player by a motor and then the disc is set in a reproducible position. Such discs have has been used extensively because of their good operability.
A conventional disc loading/unloading apparatus for slot-in type disc players includes a disc tray and a positioning mechanism. The disc tray is made movable inside the disc player between an unloading position near a disc receiving slot or a disc insert port formed on a front of the disc player and a loading position, where a disc may be played while maintained in a horizontal condition. When an operator inserts a disc into the disc insert port up to a fixed depth, the disc is pulled inside the disc player by a motor, and is loaded on the disc tray. After that, the disc tray and the disc are moved to the loading position by the motor. At the loading position, the disc is clamped by a turntable and a disc clamper set in rotatable condition, that is, in reproducible condition for playing the disc.
The positioning mechanism is provided with a pair of positioning members which are biased by a spring suspended therebetween or the like so as to hold the disc at its opposite peripheral portions in the radial direction. During the loading operation of the disc, the disc inserted into the port pushes open the pair of positioning members. When the disc is laid on the disc tray, the disc is stably held between the positioning members. After the disc tray is moved to the loading position, and the positioning members are parted from the disc, the disc is ready to be played.
When a reproduction of the disc is finished or when an eject operating element is activated, the disc tray is moved to the unloading position by the power of the motor, and then the disc is pulled out from the disc tray by the motor power. At this time, the disc pushes open the pair of positioning members once and is pushed out from the disc tray until a prescribed part of the disc is projected outside the disc insert port. Then, the operator can pull out the disc from the disc player by holding the projected portion of the disc.
However, in the conventional disc loading/unloading apparatus of slot-in type disc player as described above, the following problems arise. First, when the disc goes in and out the disc insert port, it pushes open the pair of positioning members once. No problem occurs in this phase, since an operator pushes the disc into the disc insert port by his/her hand. However, during the unloading operation, the disc must push open the disc positioning members in driving from the loading position to the unloading position by the motor power. Thus, a large load for pushing open the disc positioning members is needed from the motor. Therefore, it is necessary to use a large-sized motor having large torque. This requires that the size of the player be larger, and that greater power be consumed.
If the biasing force of the spring or the like applied to the pair of positioning members is decreased to decrease the load applied against the motor, there is a fear that the positioning of the disc may not be performed correctly.
Further, in the conventional disc loading/unloading apparatus of a slot-in type disc player, when unloading the disc from the disc player, the projection of the disc from the disc insert port is often insufficient, so that it is difficult for the operator to take out the disc from the disc player.